Understanding IAM Policies

IAM Policies are statements that define the permissions of users, groups, and applications in Scaleway Organizations.

They are composed of:

• a principal - a user, group, or application,
• one or more IAM rules - consisting of permission sets bound to a scope.
• one or more IAM conditions - defined in Common Expression Language (CEL) expressions.

PrincipalLink to this anchor

A principal is an entity that can be attached to a policy. Currently, you can attach either a user, a group, or an application to a policy. Only one principal can be attached to each policy.

RulesLink to this anchor

A rule is the part of a policy that defines the permissions of the policy’s principal, and the scope of these permissions. It consists of a scope (at Project level or Organization level) and one or more permission sets (eg. “list all Instances”).

ScopeLink to this anchor

A scope defines where the permission sets should apply. At Scaleway, a scope can be at Project or Organization level.

• Projects group your Scaleway resources (eg. Instances, Object Storage buckets, Managed Databases etc.) together. An Organization may have many Projects, or just one default Project. If you choose to define scope at Project level, you can select one, many, or all Projects. When you then define the permission sets for this scope, you can give access to different resources within the Project(s).
• an Organization is made of one or several Projects. IAM, billing, support and abuse tickets and project management are managed at Organization level, so choose an Organization scope to give access to these features.

Permission setsLink to this anchor

A permission set consists of one or multiple permissions to perform actions on resources or features. Each permission set has a clear description, e.g. InstancesFullAccess, InstancesReadOnly, RelationalDatabaseFullAccess, BillingReadOnly.

ConditionsLink to this anchor

A condition is an additional layer of restrictions for your rule. You can allow access to specific user agents or IP addresses, and allow actions to be performed only at certain dates and times. Conditions are defined through CEL expressions. In general, a condition expression consists of one or more statements that are joined by logical operators (&&, ||, or !).

Conditions can be set up and configured in the Scaleway console.

Refer to the Understanding policy conditions documentation page to learn how they are set up and how you can define them.

Example ruleLink to this anchor

The rule below defines various levels of access to different resources in Project A.

Example policyLink to this anchor

The policy below states that the application production-c can create, list, delete and manage Instances and Databases in Project A, but for Object Storage it can only list and read the resources.

Rule 1:

Rule 2:

JSON policy example

{
  "application": "production-c",
  "rules": [
    {
      "projects": ["A"],
      "permission_sets": ["InstancesFullAccess", "ObjectStorageReadOnly", "RelationalDatabasesFullAccess"]
    },
    {
      "projects": ["F"],
      "permission_sets": ["ContainerRegistryFullAccess", "ContainersReadOnly", "RelationalDatabasesFullAccess"]
    }
  ]
}

If necessary, we could add more rules to the policy, giving production-c additional permissions in other Projects, or at Organization level.